build: use own script instead of svu

We use a slightly different handling of features between prereleases.

.github/workflows/release-syncthing.yaml

@@ -25,16 +25,12 @@ jobs:
         with:
           go-version: stable
 
-      - name: Get svu
-        run: |
-          go install github.com/caarlos0/svu@latest
-
       - name: Determine version to release
         run: |
           if [[ "$GITHUB_REF_NAME" == "release" ]] ; then
-            next=$(svu next)
+            next=$(go run ./script/next-version.go)
           else
-            next=$(svu prerelease --pre-release rc)
+            next=$(go run ./script/next-version.go --pre)
           fi
           echo "NEXT=$next" >> $GITHUB_ENV
           echo "Next version is $next"

go.mod

@@ -59,6 +59,7 @@ require (
 	github.com/cenkalti/backoff/v4 v4.3.0 // indirect
 	github.com/certifi/gocertifi v0.0.0-20210507211836-431795d63e8d // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/coreos/go-semver v0.3.1 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.5 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/ebitengine/purego v0.8.3 // indirect

go.sum

@@ -46,6 +46,8 @@ github.com/chmduquesne/rollinghash v4.0.0+incompatible/go.mod h1:Uc2I36RRfTAf7Dg
 github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
 github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
 github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMnBNeIyt5eFwwo7qiLfzFZmjNmxjkiQlU=
+github.com/coreos/go-semver v0.3.1 h1:yi21YpKnrx1gt5R+la8n5WgS0kCrsPp33dmEyHReZr4=
+github.com/coreos/go-semver v0.3.1/go.mod h1:irMmmIw/7yzSRPWryHsK7EYSg09caPQL03VsM8rvUec=
 github.com/cpuguy83/go-md2man/v2 v2.0.5 h1:ZtcqGrnekaHpVLArFSe4HK5DoKx1T0rq2DwVB0alcyc=
 github.com/cpuguy83/go-md2man/v2 v2.0.5/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/d4l3k/messagediff v1.2.1 h1:ZcAIMYsUg0EAp9X+tt8/enBE/Q8Yd5kzPynLyKptt9U=

script/next-version.go

@@ -0,0 +1,118 @@
+//go:build ignore
+// +build ignore
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+
+	"github.com/coreos/go-semver/semver"
+)
+
+const suffix = "rc"
+
+func main() {
+	pre := flag.Bool("pre", false, "Create a prerelease")
+	flag.Parse()
+
+	// Get the latest "v1.22.3" or "v1.22.3-rc.1" style tag.
+	latestTag, err := cmd("git", "describe", "--abbrev=0", "--match", "v[0-9].*")
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	latest, err := semver.NewVersion(latestTag[1:])
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+
+	// Get the latest "v1.22.3" style tag, excludeing prereleases.
+	latestStableTag, err := cmd("git", "describe", "--abbrev=0", "--match", "v[0-9].*", "--exclude", "*-*")
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	latestStable, err := semver.NewVersion(latestStableTag[1:])
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+
+	// Get the commit logs since the latest stable tag.
+	logsSinceLatest, err := cmd("git", "log", "--pretty=format:%s", latestStableTag+"..HEAD")
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+
+	// Check if the next version should be a feature or a patch release
+	nextIsFeature := false
+	for _, line := range strings.Split(logsSinceLatest, "\n") {
+		if strings.HasPrefix(line, "feat") {
+			nextIsFeature = true
+			break
+		}
+	}
+	next := *latestStable
+	if nextIsFeature {
+		next.BumpMinor()
+	} else {
+		next.BumpPatch()
+	}
+
+	if latest.PreRelease != "" {
+		if !*pre {
+			// We want a stable release. Simply remove the prerelease
+			// suffix.
+			latest.PreRelease = ""
+			fmt.Println(latest)
+			return
+		}
+
+		// We want the next prerelease. We are already on a prerelease. If
+		// it's the correct prerelease compared to the logs we just got, we
+		// should just bump the prerelease counter.
+		if next.LessThan(*latest) {
+			parts := latest.PreRelease.Slice()
+			for i, p := range parts {
+				if v, err := strconv.Atoi(p); err == nil {
+					parts[i] = strconv.Itoa(v + 1)
+					latest.PreRelease = semver.PreRelease(strings.Join(parts, "."))
+					fmt.Println(latest)
+					return
+				}
+			}
+		}
+
+		// Otherwise we generate a new rc.1 for the correct next version.
+		next.PreRelease = suffix + ".1"
+		fmt.Println(next)
+		return
+	}
+
+	if nextIsFeature {
+		latest.BumpMinor()
+	} else {
+		latest.BumpPatch()
+	}
+	if *pre {
+		latest.PreRelease = suffix + ".1"
+	}
+
+	fmt.Println(latest)
+}
+
+func cmd(name string, args ...string) (string, error) {
+	cmd := exec.Command(name, args...)
+	bs, err := cmd.CombinedOutput()
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(string(bs)), nil
+}